Are the spyder feedneck spacing and the phantom feedneck spacing the same?

Not quite. The spyder necks on the phantoms as mentioned above don't fit "*exactly*. It is close enough that it usually works, but if you get big bore paint it can sometimes get stuck (easiest way to avoid this, if you're doing a SC/OC sniper as I assume, would be to cut the breach hole slightly larger on the front, making it an oval. Works as is when using normal paint, user preferance.)